well its mounted, now as root run the following, also please use code flags it really makes life much simpler to read the copy/paste you put on the screen thank you.
ls -laF /media/ExtraNas
they should look something like this:
[user@centos ~]$ df -Th
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/vg_centos-lv_root ext4 50G 18G 29G 39% /
tmpfs tmpfs 3.9G 4.0K 3.9G 1% /dev/shm
/dev/sdb1 ext4 485M 149M 312M 33% /boot
/dev/mapper/vg_centos-lv_home ext4 1.8T 974G 717G 58% /exports/centos
/dev/sda1 ext4 1.4T 832G 475G 64% /exports/NFS_TV_Shows
/dev/sdc1 ext4 3.6T 2.0T 1.5T 58% /exports/New
[user@centos ~]$ ls -laF /exports/New/
drwxr-xr-x. 4 user user 4096 Aug 6 16:03 ./
drwxr-xr-x. 5 root root 4096 Aug 2 2013 ../
-rw-r--r--. 1 user games 6148 Jan 19 23:50 .DS_Store
drwx------. 2 user user 16384 Aug 4 2013 lost+found/
drwxrwxr-x. 8 user user 4096 Aug 28 06:43 public/
Note that one of the hidden files (.DS_Store) is a different group then the directories. thats ok. it tells you something about the UID/GUID of the user who created the file. FYI its created by my FileZilla client even though it uses the same user user UID/GUID as my normal user. due to FileZilla there are some issues with some files. its easy to fix and to be blunt does not affect access from my normal user via any other means of access.
now the reason I want you to post the ls -laF (those are lower case L's btw) is so you can look at the user and group ownership of your mount point.
/media/foo is typically created automagically via the GUI so the permissions should be correct. As it is a Linux formatted partition you should also be ok. worst case you go in as root and fix things